who would win?

Of course Ryuk would win. Because he could just write C.C's name down in his death note, whilst C.C would have to get her hands on a death note just to see a shinigami=game over.

Wow you thought this one out laughingman im impressed...i think the death note is meant for humans but isnt a witch considered a human just with powers that came from the devil...as for falling in love he doesnt need to see her all he needs is her name and its game over I vote ryuk

Anyway how about eren jaeger from attack on titan http://vignette1.wikia.nocookie.net/shingekinokyojin/images/3/3e/Episode_8.png Against kaneki from tokyo ghoul http://fc09.deviantart.net/fs70/i/2014/218/d/1/kaneki_ken_by_p_bee-d7twvni.jpg Note:its eren without his titan power